Hydraulic cutting machine



April 7, 1942.-

W. J. RIDDLE HYDRAULIC CUTTING MACHINE 2 Sheets-Shet 1 Filed March 28,194,1

lll

l l M V April7,1942.' w1 mDDLE d .2,278,713-

HYDRAULIC CUTTING MACHINE .y

Filed Maron 28, 1941y 2 sheets-sheet 2 ATTOWEVS Patented Apr. 7, 1942 toThe Hydraulic Development Corporation, Inc., Wilmington, Del.,a'corporation of Delaf Ware Application March 28, 1941, serial 15claims.

This invention relates to hydraulic machinery and, in particular, tohydraulically operable cutting machines.

It is an object of the. invention toy provide a cutting machine with ahydraulically operable y cutter and a hydraulic work piece holder, inwhich the work piece .holder is operable hydraulically without actuationof the cutter.

Another'object of the invention consists in the provision of a hydrauliccutting machine, in which the operation of the cutter automaticallyinitiated in response to a predetermined pressure with which the workpiece to be cut is pressed upon a support therefor. Y

It is another object of the invention to provide a cutting machine, inwhich the last portion of the cutting stroke is slowed down.

No. scam It is another object to provide a cutting mal chine, in whichthe cutter' is hydraulically operated by a fluid motor having adi a':icing means and retracting means, and in which fluid expelled from saidretracting means during the operation of said advancing means is usedlfor assisting, the latter. n

Still another object consists in the provision of a cutting machinecomprising a iluid motor with advancing and retracting-means, in which Athe release of uid from the retracting means of said uid motor isresponsive to the admittance of pressure iiuid to the advancing mean o fy said motor.

It is a still further object of the invention to provide a cuttingmachine vwith a fluid lmotor having advancing and retracting means, inwhich a pilot unloader valve is providedfor allowing release of fluidfrom said retracting means only when a predetermined pressure has builtlup in said advancing means.l

These and other objects and advantages of the invention will appear moreclearly from the folmounted therein a piston 2 with apiston rod 3.The'said cylinder pistons and piston rods are substantially equal.Connected to the piston rods 3-'in any convenient manner is the cutterbar 4 for cutting the work piece.

The main' cylinders I arestationary and supported by the press head 5`which is spaced from and connected in any convenient manner with thepress bed 6 for .supporting the1 work piece.

-A work piece placed on 'the press bed 6 is clamped or held thereagainstby means of hold-down .cylinders 1, the effective number of which may bevaried according to .the size of the'work piece, which may b e sheetmetal, paper, or the like.

Reciprocably .mounted in eachv hold-down cylindex' 1 is a piston 8 witha piston' rod 9 adapted to engage the work piece. Between the lowersurface of the piston 8 and the bottom of the cylinder 1 is arranged alspring I0 for lifting or returning,- the piston 8 to its initialposition when the hold-down or clamping operation has been l completed.l Y I The upper. portion of each of the hold-down cylinders 1communicates with a conduit I l leading into a'common conduit I2 whichin its turn is connected to a conduit I3, comprising an adjustable'chokeI4. The opening in the choke valve Il determines the rate at. whichpressure iluid enters the hold-down cylinders -1. The `conduit I3 leadsto an adjustable admission valve I5 of the type shown in Figure 2, whichvalve will be described in detail later.

Communicating with the admission valve I5 is a conduit I6 leading intoaconduit I1, which communicates with the upper portion of the two maincylinders I. The lower portion of the main cylinders l isadapted tocommunicate with each other through a conduit I8. The ports I9 at whichthe conduit I8 communicates -with the lowing specication in connectionwith the accompanying drawings, in whichz Figure .1 is a front view of ahydraulically operable cutting machine according to the invention.

Figures 2 and 3 illustrate valves used in the hydraulic circuit of the-present invention.

Figure 4 illustrates diagrammatically the hydraulic circuit of a cuttingmachine according to the invention.

Structural arrangement Referring to the drawings in detail, the cuttingmachine shown therein comprises a pair of main cylinders I, each ofwhich has reciprocably main cylinders I are adapted'to be by-passed' byconduits 20 pertaining toeach of the main cylinders l comprising a chokevalve 2l, and communicating with al conduit 22 respectively leading intothe cylinders I adjacent the bottom portionthereof. Each of the conduits22 com- .prises a. check valve 23, which opens in the direction of therespective arrow.

The admission valve I5 may be by-passed by a conduit 24 comprisinga-check valve 25 and communicating with its conduits I6 and I3arespectively, which latter is connected4 to the admission valve I5.vConnected to the conduit I8 is a conduit 26 leading to a pilot unloadervalve A 21 of the type shown in Figure 3, which will likewise bedescribed later. A pilot line 28 in- 21 through a leakage line 31.

Aterconnects the pilot unloader valve 21 and the conduit Ita. A furtherconduit 29 comprising a check valve 38 also leads from lthe pilot unloader valve 21 to the conduit I3a, which is connected to a four-wayvalve 3 I Also connected to the four-way valve 3|- is a conduit 32comprising a shutoi valve 33 and a check valve l34 and leading tothe1c'onduit'28.

prising a needle valve 39 and leading to the conduit 26. Another line,40, comprising a check valve 4| is adapted to effect communicationVbetween the tank 31 and the conduit. I1. The tank 38 is also connectedwith a conduit l42 leading movedbeyond the same by a predetermineddistance.

Referring now tothe valve of Figure 2, the same comprises substantiallya casing 19 which is joined to a valve housing 88, for instance, by athreaded connection. Reciprocably mounted partly within the casing 19and the valve housing 88 is a plunger 8| which is vfree to move up 4anddown against the pressure of a compression spring 82, which makescontact against the head 83 on the plunger 8|.v The compression spring82 `may be adjusted to any desired pressure by to the suction side of apump 43, the pressure side of which is connected to the conduit 44comprising a pressure relief valve 45, which inits structure maycorrespond to the valve shown in Figure 2.

The relief valve 45 is adapted'to communicate on one hand throughconduit 46 with the'tank 36 and on the other hand through conduit 415with the four-way valve 3l. The iour-way'valve 8| is so arranged thatwhen its valve member (not shown) is moved into its left-hand end.position with regard to Figure 4, the conduit 41 communicates with `theconduit I3a, whereas when the valve member of the four-way valve 8| isshifted to its right-hand end position, the conduit 41 communicates withthe conduit 32. When the valve member of the four-way valve 3| is in itsintermediate position, the conduit 41 communicateswith the conduit 35.The fourway valve 3| does not form a part of the present invention andfor a more detailed description thereof, reference may be had to PatentNo. 2,109,162 to Boehle.4 The valve member of the valve 3| is connectedwith a shift arm 48 pivotimmature sl which carnes a third switch made 82adapted to electrically connect the line 83 comprising a normallyvclosed limit switch 84 and leading to the main supply line 85 with theline 86 connected to one end of the solenoid 61. The solenoid 81 is,furthermore 'connected with a line 88 adapted by closureof the pushbutton 69 to be electrically connected with the line 10.1eading to themain supply line 65. 'I'he other end of the solenoid 61 is connected, bymeans of line 1I, with the main supply line 12which is also connectedwith the line `58. 1

Thearm 13 of the three-arm lever 50 is continuously urged inanti-clockwise direction by..

means of a spring 14 attached to the arm 13,

which arm is also pivotally connected to a push rod `1li. 'I'he push rod15 has adjustably mounted thereon a collar 18 adapted to be engaged byan arm 11 carried by the cutter bar 4. Also carried by the cutter bar 4is an adjustable abutment screw 18, which is preferably so adjusted thatit opens the limit switch 84 after the cutter bar 4 has completely cutthev work piece and rotating the adjusting screw 84, which pushes Vthespring cap 85 downwardly against the compression spring 82. 'Theadjustment is maintained in locked position by the lock nut 86.

Contained within the' upper part of the valve housing 88 is a plungerlifting chamber 81 through which the plunger 8| passes. Within thischamber, the plunger diameter is enlarged to form the differentiallifting area 88 which is of annular form. One side of the plungerlifting chamber 81 has the inlet port 89 passing through the walls ofthe valve housing 80 where it con tinues in the pilot line 28 (Figure4).

- The chamber 90. below the lower end of the plunger 8| .isconnectedwith the conduit 29.

The valve chamber 9| of the valve housing 80 is connected with theconduit 26, while the casing 19 is connected with the leakagev conduit31 leading to the tank. The device of Figure 2 operates in suchv amanner that when the pressure in the plunger lifting chamber 81 reachesa predetermined value, the plunger 8| is lifted by lthe uid acting onthelifting area 88 so that i'luid from conduit 28 may pass through thevalve chamber 9| into the conduit 29.

Referring to Figure 3, the valve shownA therein is somewhat similar tothe valve of Figure 2, and similar parts are, therefore, designated withthe samerreference numerals, however, with the additional letter a. Incontrast to the valve of Figure 2, the valve chamber 9Ia communicates onone hand with the conduit I3 and on the other hand with the conduitv I3aso that a continuous'connection is established between the conduits I 3and I3a, irrespective of the position of the plunger 8Ia. The chamber98a below the lower end of the plunger 8Ia communicates with the conduitI6. When a predetermined pressure is built up in the valve chamber 9Ia,this pressure acts on the lifting area 88a, thereby lifting the plungerv8Ia and'establishing communication between the conduit I6 and theconduits I3 and I3a.

Operation Assuming that all parts of the device shown in the drawingsoccupy the position of Figure 4, and that it is now desired to start aworking cycle, the operator pushes the push button 69, thereby closing acircuit comprising the main supply line 85, lines 10 and 68, solenoid61, line 1I and main supply line 12. Asa result thereof solenoid 61 isenergized and causes the armature 6| to move upwardly so that the switchblade 62 establishes a lholding circuit for the solenoid 61, while theswitch blades 59 and 60 close the energizing circuit for the solenoid54. As a result of the enerestablishes connection between the conduit`41V and the conduit I3a, while simultaneously establishing connectionbetween the conduits 35 and 32.

Assuming that previously the pump 43 was' solenoid 54. 'rhesprmg 14 thenshifts the threestarted, pressure fluid is now delivered by the pump 43through the conduit 41, the four-way valve 3l, the conduit I3a, valvechamber 9Ia of the valve I5, vthe conduits I3 and I2 and into thehold-down cylinders 1 where the pressure fiuid acts upon the respectivepistons 8 and moves the latter downwardly against the thrust of thesprings I0 so that the piston rods 9 grip the work piece to be cut.

When a predetermined pressure has built up in the cylinders 1 so' thatthe work piece is' pressed with a predetermined pressure against itssupport or press bed 6, this pressure overcomes the thrust of the spring82a so that the plunger 8Ia is lifted, thereby establishing connectionbetween theconduit I 6 and the conduits I3 and I3a. As a result thereof,pressure fluid from the con- Y duit I3a now passes through conduit I6into the conduit I1 from where it flows into the main cylinders I abovethe pistons 2. This pressure acting upon the pistons 2 causesV thelatter to compress the fluid in the. main cylinders I below the pistons2 which, up to this time, could not escape since the check valve 34allows passage of fluid only in the direction indicated by the arrowpertaining thereto, while the needle valve 39 is closed and the plunger8'I of the valve 21is in its lower position, in which it preventscommunicaticn betweenthe conduits 26 and 29. However, since thepressure, now acting upon the pistons-2 and c-onveyed thereto throughthe conduit I1, also prevails in the pilot line 28, this pressure isconveyed into the-lifting chamber 81 valve 3D into the conduit 29, andis then conveyed.

through the conduit I3a, the valve I5 and the conduits I6 and I1 intothe upper portion of the main cylinders I. In other words, the pressureuid expelled by the pistons 2 aids the downward movement of the saidpistons.

As will be seen from the drawings, before the pistons 2 have completedtheir downward stroke, i. e., preferably before they have completely cutthrough the work piece, the pistons 2 close the ports I9 so that thefluid beneath the pistons 2 can escape from the main cylinders I onlythrough the conduits 22, the choke valves 2I and the conduits into theconduit I8. Depending on the adjustment of the choke valves 2|, the lastportion of the downward movement or cutting stroke of the pistons 2 may'be slowed down to any desired degree. This slow-down movement preventsany damage to the work piece, whichv otherwise might be caused if thecutter bar 4 cuts through the work piece atahigh speed and then suddenlymeets no further resistance.

When the cutter bar 4 has completely cut arm lever in anti-clockwisedirection and by means of the shiftarm 4'8 shifts the valve member ofthe four-way valve-3l into its left-hand endposition, therebyestablishing hydraulic connection between the conduits 41 and 32, whilesimultaneously effecting communication between the conduits I3a and 35.Pressure fluid is now delivered by the pump 43 through conduit 41,four-way valve 3|, conduit 32, the open shutoff valve 33, check valve34, conduits 26, I8 and 20, check valves 23 and conduits 22 into thelower portion of the main cylinder I. Consequently, the pistons 2 starttheir upward or retraction movement, while expelling the fluid in theupper portion of the main cylinders I into the conduit I1, from where itows through conduits I6 and 24, check valve 25, conduit I3a and theconduit 35 into the tank-36. y

Since, due to the hydraulic communication now established between theconduits I3a and 35a pressure drop occurs in the conduits I3 and I2, thesprings I0 beneath the hold-down pistons 8 immediately return thecutterbar 4 to its lifted position, thereby enabling the operator to removethe cut off portion of the work piece and to place thework piece into aynew -position for a further cut, While the cutter bar 4 is still movingto its retracted position.

Due to the pressure drop inthe conduit I3a, the pressure in the pilotline 28 likewise drops so that the compressing spring 82 of the valve 21again causes the plunger 8l t0 closethe hydraulic communication betweenthe conduits 26 and 29. l v

When the pistons 2 and the cutter bar '4 connected thereto havereached apredetermined position during the said retraction stroke, the arm 11engages the collar 16, thereby lifting the push rod 15 so that thelatter, through the intervention of the three-arm lever 50 and the shiftarm 48, moves the valve member of the four way valve 3I to itsintermediate position, in which the conduit 35 is connected with theconduit 41. When this connectionl has been established, the pressure uiddelivered by the pump 43 is merely circulated through the conduit 41,the four-way valve 3I, conduit 35 and tank 36, from where it ows throughthe conduit 42 tothe suction side of the pump 43. As a result thepistons 2 and, therefore, the cutter bar 4 come to a halt.

Since, as previously mentioned, the pilot unloader valve 21 had closedthe hydraulic connection between the conduits 26 and 29, the pressure inthe lower portion of the main cylinders I is `maintained and the pistons2 are held in their llfted posit1on. A new cycle may then be started byagain actuating the push button 69.

In order to assist in setting up the cutter bar 4,

provision is made to inch the' cutter bar slowly.

is running. The needle valve 39 may then be opened to allow the weightof the pistons 2 to expel any desired restricted quantity of iiuid fromthe lower portion of the main cylinders I into the mature 6I withitsblades 62, 59 and 68 drops back to its open position, therebydeenergizing the conduits I8, 26 and 38, from where the fluid may passinto the tank 36. In this way any gradual downward movement of thepistons 2 and the cutter bar 4 connected thereto may be effected.

Fluid is supplied to the upper portions of the ranlam cylinders Ithrough the small check valve vIf, for some reason, any .undue pressure'fshoulddevelop' in the' conduit 44 or the conduit 41,1thispressure willbe released into the tank 3i =throughthe valve 45` which, as previouslymen- 'f tioned, corresponds in yits construction to that of the Valvel5. Y

It will be understoodthat I desire to comprehend within my inventionsuch modifications as come within the scope of the claims and theinvention.

Having now fully described my invention, what I claim as new and desireto secure by Letters I Patent is:

means hydraulically `'connected with said pressure responsive means forallowing iiow of iluid from said retracting means to said advancingmeans, while preventing the flow of iluid in the reverse direction.

5. In a hydraulic system for a cutting machine, a main plunger havingassociatedtherewith uid operable advancing and retracting means forvreciprocating said plunger, a fluid operable auxiliary plunger, conduitmeans for hydraulically interconnecting said advancing means and saidauxiliary plunger, meansarranged in said con- 1. In a hydraulicallyoperable cutting machine,

a main plunger having associated therewith fluid operable advancing andretracting means for reciprocating said plunger, cutting means operduitmeans and responsive to a predetermined pressure on said auxiliaryplunger for eiiecting hydraulic connection betweensaid advancing meansand saidl auxiliary plunger, and valve means hydraulically connectedwith said retracting means for preventing escape of iluid from saidretracting means prior to the establishment of said predeterminedpressure to prevent acciy dental advancing movement of said mainplunger.

movable independently of said main plunger for holding a work piece tobe cut, said holding plunger being adapted hydraulically to be connectedwith said advancing means, and pressure responsive means `responsive toa predetermined pressure on said holding plunger for establishinghydraulic connection between said holding plunger and said advancingmeans.

3. In a hydraulically operable cutting machine, a cylinder, adouble-acting plunger reciprocably mounted in said cylinder, cuttingmeans operatively connected with said plunger, a iiuid source adapted tosupply pressure uid to saidcylinder for actuating said plunger, workpiece holding means for vholding a work piece during the cuttingoperation, iiuid operable advancing means associated with said workpiece holding means for advancing the same, conduit means for conveyingpressure fluid from said iiuid source to said fluid operable advancingmeans independently of the supply of pressure fluid to said cylinder,yielding means associated with said holding 6. In a hydraulicallyoperable cutting machine, a main cylinder, a double-acting main plungerreciprocable in said main cylinder, a cutter bar operatively connectedwith saidl main plunger, an auxiliary uid operable plunger for holding awork piece during-the cutting operation, a fluid source adapted tosupply 'pressure fluid to said main plunger and saidauxiliary plunger,conduit means for hydraulically interconnecting said iiuid source withsaid plunger, valve means in said conduit means for sequentiallyadmitting pressure uid from said iluid source first to said auxiliaryplunger and thereafter to said main plunger, and fluid pressurevresponsive means hydraulically connected with the'retraction side ofsaid main plunger and responsive to a predetermined pressure on theadvancing side oi' said means and constantly urging said holding meansinto retraction position, and iiuid pressure responsive means responsiveto a predeterminedl pressure on said work piece holding means forestablishing hydraulic connection between said fluid source and one sideof said cylinder and for conveying iiuid expelled from the other side ofsaid cylinder to said iirst mentioned side of `said cylinder to assistthe advancing movement of said plunger.

4. In a hydraulically operable cutting machine, a main plunger havingassociated therewith fluid operable advancing and retracting means forselectively advancing orretracting said plunger,

cutting means operatively `connected with said4 main plunger, a fluidoperable holding'plunger movable independently of said main plunger forholding the work piece to Vbe cut, said holding plunger being adaptedhydraulically to be connected with said advancing means, pressureresponsive means responsive to a predetermined pressure on said holdingplunger for establishinghydraulic connection between Isaid holdingplunger and said advancing means and between the latter and saidretracting means, and valve -main plunger for conveying pressure iiuidexpelled from the retraction side oi said main plunger to the advancingside thereof.v

7. In a hydraulically operableA cutting machine, a main cylinder, adouble-actingmain plunger reciprocably mounted insaid main cylo inder,cutting means operatively connected with said main plunger, said maincylinder having two ports spaced in the longitudinal direction of saidmain cylinder, Achoke means associated with one of saidv ports forrestricting the escape oi iluid from said main cylinder when said mainplunger approaches the end of its cutting stroke, an auxiliary uidoperable plunger for holding a work piece during the cutting operation,and valve means hydraulically connected with said auxiliary plunger andadapted to prevent the supply oi' pressure iluid to the advancingside ofsaid main plunger prior to the-,establishment of a predeterminedpressure on said auxiliary plunger.

8. In a hydraulically operable cutting machine, a main cylinder, adouble-acting main plunger reciprocably mounted in said main cylinder,cutting means operatively connected with said'main plunger, said maincylinder having two ports spaced in the longitudinal direction of saidmain cylinder, choke means associated with one of said ports forrestricting the escape of iluid from said main cylinder when said mainplunger approaches the end of its cutting stroke, bypass y or to saidauxiliary plunger, control valve means hydraulically connected with saiduid source for preventing hydraulic communication between the latter andthe advancing side of said ymain plunger prior to the establishment of apredetermined pressure on said auxiliary plunger, and by-pass valvemeans for hydraulically by-passing said control valve means during theretraction stroke of said main plunger to effect hydraulic communicationbetween said advancing means and said fluid source.

.10. In a hydraulically operable cutting machine, a main plunger, fluidoperable advancing and retracting means associated with said plunger foractuating the same, cutting means operatively connected with said mainplunger,` a uid operable auxiliary plunger for holding a work piece tobe cut, a fluid reservoir, a pressure iiuid pump having its suction sideconnected with said reservoir and adapted selectively to supply pressurefluid to said auxiliary plunger and said advancing means or to saidretracting means, iirst conduit means connecting said fluid reservoirwith said advancing means, a check valve agranged in said first conduitmeans and adapted to admit fluid from said reservoir to saidadvancchine, a main plunger having associated therewith uid operableadvancing and retracting means for actuating said plunger, a constantdelivery pump adapted selectively to supply pressure fluid to saidadvancing and retracting means, a four-way valve adapted selectively toconnect said pump with said advancing means or said retracting means orto by-passthe delivery of said pump to an exhaust, cutting meansAoperatively connected with said main plunger, an

auxiliary plunger adapted hydraulically to be connected with said pumpto lexert holding pressure on awork piece to be cutyfluid pressureresponsive means hydraulically connected with said auxiliary plunger andadapted in response to a predetermined pressure on thelatter to efiecthydraulic communication between the advancing side of said main plungerand said pump, and valve means operable in response to a predeterminedpoint of travel of said main plunger after completion of the cuttingoperation for reversing hydraulic communication between said.pump andsaid advancing and lsaid retracting means.

13. In a hydraulically operable cutting ma chine, a plurality ofdouble-acting main plungers,

cutting means-'operatively connected with said main plungers, conduitmeans connecting the advancing sides 0f said main plungers and beingadapted hydraulically to be connected with the pressure side of apressure pump, a plurality of auxiliary plungers adapted to be suppliedwith ing means, but not vice versa, controlling means for sequentiallyadmitting pressure iiuid to said auxiliary plunger and said advancingmeans, second conduit meansadapted to supply pressure uid 4from saidpump to said retracting means, a shutoff valve in said second conduitmeans for interrupting hydraulic communication between the pressure sideof said pump and said retracting means, third conduit means adapted toestablish hydraulic communication between said retracting means and saidreservoir, and adjustable choke means for varying the rate of ow of uidfrom said retracting means to said reservoir.

11. In va. hydraulically operable cutting machine, a main plunger havingassociated therewith fluid operable advancing and retracting means forreciprocating said plunger, cutting means operatively connected withsaid plunger, a fluid operable auxiliary plunger for holding a workpiece during the cutting operation, a pressure :duid source forsupplying pressure fluid selectivelyA to said auxiliary plunger and saidadvancing means or to said retracting means, fluid pressure responsivemeans hydraulically connected with,said iiuid source for admittingpressure iiuid 'to said advancing means in response to a predetermineduid pressure on said auxiliary plunger, and yielding meansresponsive tothe release of fluid pressure on said auxplunger for spacingy the samefrom the work piece.

12. In a hydraulically operable cutting mahydraulically connectedpressure liiuid from said pump to hold a work piece during the cuttingoperation, yielding means continuously tending'to space said aux-`iliary plungers from said work piece, further conduit meansinterconnecting the retraction sides of said main plungers, rst controlvalve means with said auxiliary plungers for preventing supply ofpressure fluid to the advancing sides of said main plungers prior to theestablishment of a predetermined pressure on said auxiliary plungers,second control valve means for preventing the escape of fluid from theretraction Vsides of said main plungers priorto the establishment of apredetermined pressure on the advancing sides of said main plunger, andby-pass valve means for bypassing said nrst and second control valvemeans during the retraction stroke of said main plungers.

14. In a hydraulic system, the combination of A a hydraulic hold-downmeans, a hydraulically operable shear, and means to bring about theactuation of the shear upon the accomplishment of a predeterminedpressure on said hydraulic holddown means.

l5. In a hydraulically operable shear, a main plunger having associatedtherewith fluid operable advancing and retracting means forreciprocating said main plunger, a uid operable auxiliary plunger,conduit means hydraulically interconnecting said advancing means andsaid auxiliary plunger',4 and means arranged in said conduit means andresponsive to a predetermined pressure on said auxiliary plunger foreffecting hydraulic communication between said advancing means and saidauxiliary plunger.

WILLIAM J. RIDDLE.

